If you’re like most mobile device users, you don’t want to pay anything for apps. Zero, zilch, niente. But do you pony up to get rid of ads? Or unlock additional features or content? And if so, how much are you willing to spend?

In July 2013, Flurry, an app analytics service provider, released the results of its app pricing research. The gist: Consumers overwhelmingly prefer free apps, even if they're packed with ads.

In 2013, 90 percent of all iOS apps were free, according to Flurry. Android users tend to be even less willing to pay for apps, Flurry found. Among all app users, iPad owners tend to be the "bigger spenders," and the average price of iPad apps in use as of April 2013 was more than 2.5 times greater than the cost of iPhone apps and more than 8 times pricier than Android apps, according to Flurry.

In short: Most people don’t spend money on apps. "Developers of some specialized apps may be able to monetize through paid downloads, and game apps sometimes generate significant revenue through in-app purchases," Flurry posted on its blog. And yet, "since consumers are unwilling to pay for most apps, and most app developers need to make money somehow, it seems clear that ads in apps are a sure thing for the foreseeable future."

Ads are unavoidable in our culture, of course. It’s the price we pay for, say, network TV programs. Ads are OK for certain types of apps, in my opinion — especially those you don’t spend much time using.

The Weather Channel app is one example. The free version for Android and iOS includes small ads that run along the bottom of the app. There’s also a separate, free Weather Channel for iPad app. I notice the ads in these apps, but they’re not annoying. And I rarely spend more than a couple of minutes in the app, checking the local forecast.

Alternatively, I could spend $4 on The Weather Channel Max, an iOS-only app that banishes the ads and offers some additional features, such as an "Expect Rain" tab on the "Now" screen. For me, though, the $4 isn’t worth it, especially when there are so many awesome free weather apps — without ads. (Yahoo Weather comes to mind.)

Now let’s look at the new Ken Burns iPad app, which I reviewed Thursday. The app is elegantly designed and provides tons of clips from Burns’ documentaries about American history. It's also free...up to a point. Want to watch the clips in the Innovation playlist? No problem, have at it. But should you want to view other clips, it’ll cost you $10 to unlock them.

Is $10 too much? Some will undoubtedly think so. But I’d argue it’s not. Maybe that’s because I used to review CD-ROMs for Macworld magazine. (Remember CD-ROMs?) Many of the discs cost $20 to $100 — and that was 20 years ago. The Ken Burns app feels like the equivalent of a CD-ROM back in the day.

Comparatively, then, $10 for the app seems like a good value, especially if you’re an American history buff, a Ken Burns fan, and you don’t want commercials intruding into what has been designed to be an "immersive" experience. Unlike, say, The Weather Channel app, the Ken Burns app is something you’d want to spend a fair amount of time using. And for me, ads in such an app would be truly annoying.

I also paid $10 a piece for Apple’s iOS productivity apps before Apple made them free to those who bought recent iDevices. I had no qualms about these purchases, as the apps have enabled me to be productive in places I’d never have been able to get work done before.

One example: While stuck in a long checkout line during the holidays, I was able to make some edits to an article on my iPhone using Apple’s Pages, then send the revisions to my editor, who needed them ASAP — all before I reached the cashier. That’s worth $10 to me.

Free apps always come with a price, of course, whether it’s exposure to ads, limited features, or, unfortunately, risks to your privacy. Ultimately, the value of any app is in what it enables you to do or how it enriches your life or knowledge. So I’ll pay $10 — now and then — for a truly valuable app.

What’s the most you’ve paid for an app, and why did you buy it? Did you regret it? Please share your experiences in the comments below.

James A. Martin is a seasoned tech journalist and blogger based in San Francisco and winner of the 2014 ASBPE National Gold award for his Living the Tech Life blog on CIO.com. James is also a content marketing consultant.